Pain

Pain

Pain, both acute and chronic, afflicts millions of people around the world. Pain can be categorized in different ways, but one of the most common is nociceptive versus neuropathic pain.

Nociceptive pain is the result of activity in signaling pathways caused by actual tissue damage or potentially tissue-damaging stimuli. Examples of nociceptive pain include postoperative pain, arthritic pain and pain associated with sports injuries. Nociceptive pain is usually acute and develops in response to a specific situation. It tends to disappear when the affected body part heals.
The body contains specialized nerve cells called nociceptors that detect harmful stimuli or things that can injure the body, such as extreme heat or cold, pressure, crushing and chemicals. These warning signals are then transmitted along the nervous system to the brain, resulting in nociceptive pain.

This happens very quickly in real time, as when people quickly remove their hands if they touch a hot oven or stop bearing weight on an injured ankle. Other examples of nociceptive pain are post-operative pain and visceral pain. Neuropathic pain is often chronic and is initiated by dysfunction or damage to the nervous system. Chronic pain is a disability that affects every aspect of the patient’s life, which includes the ability of the individual to work and engage in social and leisure activities. Neuropathic pain affects a total of approximately 7–8 percent of the adult population. People with some conditions, such as diabetes and HIV, are affected to a greater extent where approximately 25 percent and 35 percent respectively experience neuropathic pain.

Peripheral neuropathic pain results from various types ofdamage to the nerve fibers, such as toxic, traumatic, metabolic, infectious or compressional injuries. Common symptoms are painful tingling or itching that can be described as a stabbing or burning pain, including a sensation of getting an electric shock. Patients may also experience allodynia (pain caused by a stimulus that usually does not cause pain) or hyperalgesia (increased pain from a stimulus that normally provokes pain). Three common conditions of neuropathic pain are painful peripheral neuropathy caused by conditions such as diabetes, painful postherpetic neuralgia (shingles), and neuropathic pain induced by chemotherapy.

Prevalence

An estimated 50 million adults in the US experience chronic or severe pain, and more Americans suffer from pain than diabetes, heart disease and cancer combined. The data from Europe show similar results and health and socioeconomic costs are estimated at 3–10 percent of gross domestic product in Europe. The neuropathic pain market is characterized by high unmet medical need in all indications and in all major markets, where only half of patients respond to existing treatments. The patient population is expected to continue to grow, due to factors such as an aging population, an increased incidence of type 2 diabetes, and cancer that requires chemotherapy. The global market for
neuropathic pain was valued at about USD 11 billion in 2020 and is expected to grow to USD 25 billion by 2027.

Treatment

There is currently a major medical need for several different severe pain conditions. For example, only about 50 percent of patients with neuropathic pain respond to existing treatments. Because of the risk of abuse, overdose and secondary injuries, doctors nowadays avoid prescribing opiates as first-line treatment for pain. Despite this treatment problem they are still frequently used, and therefore the need for new non-opiate treatments is great.